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[AKTICLK .-..-KXTltACTKl) FUOJI THK IJULLETIN (IF 'niK V. S..KIS 

KOI: 1895. Pases 311 tip :i24. riair ri:>. ; 



NOTES ON FISH-CULTURE IN GERMANY. 



Notes (»n Intensive Pond-Culture ;it Sandfort. 
Notes on the Rearing of Yearliniy; Trout at Sandfort. 
Fish-Cultural Meth(»ds at the .Agricultural School at Freisinu;. 
The Course of Instruction of the Bavarian Fisherv .Yssociation. 



WASHINGTON: 

GOVKKNMENT I'KINTlNCf OFFICE. 
189.5. 



[AUTiri.E r..-KXTl:ACTEI) Fl'.OM THK 13ULLETIX OF THE U. S. FISH COMMISSION 
FOU l.S!i:.. I';i';<s :ill l.i 324. I'Iaf<- .'.ri. | 



L^{ MAR 12 < 896 ]' 



NOTES OX FISH-CULTUKE IN GERMANY. 



/\^^^UL-^c.^ ^V 




X(»tcs oil liitc'nsi\c I'lMid-Cultiia" at Saiidtort. 
Notes on tlic Kcarini; of Vcarliiiy; Trout at Sandfort. 
Fish-Cultural MetJKHls at the .\i!;riculturai School at Freisin^. 
The C(Uirse of Instruction of the Bavarian Fishery .Association. 



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'AO 







WASHINGTON: 

GOVKKNMENT PRINTING OFFICE. 

1895. 



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5-NOTES ON FISH-CULTURE IN GERMANY. 



NOTES BY S. JAFFE OX INTENSIVE POND-CULTURE AT SANDFORT.' 

lu my pamphlet eutitled "Trout-culture" (published by liockhorst, Osuabriick), 
I have earnestly warued persons who carry on pond-culture on a small scale not to 
introduce into their pond.s artificial food that can not be reproduced in the pond itself. 
They should till their ponds the same as their fields, and stock them only with fish 
which the water of the pond will feed without much aid. They should cultivate and 
increase the live pond-food by introducing snails, mussels, small crustaceans, and 
useful aquatic plants, but should avoid all dead food. 

Wherever water, food, and energy are found, there is no reason why intensive pond- 
culture should not be carried on. I would, however, lay special stress on the fact that 
this pond-culture can become remunerative only where there is ample water, food, and 
time. The principles laid down in this treatise have been successfully followed at 
Sandfort and other establishments founded on the same plan. 

The water of an establishment where trout are to be raised for market should 
come from ample and steady springs; the ponds should be near, but not too close to the 
springs, which near their origin contain very little oxygen. It is useful to introduce 
brook or river water into the pond, so as to occasionally render the water turbid; 
but river water alone is rather hurtful on account of the rising temperature. To make 
the water in the ponds occasionally tuibid is useful, not only because the particles 
of soil which are precipitated act as a disinfectant on the remnants of food, but also 
because they furnish the trout, particularly in cemented and other entirely arti- 
ficial basins, those i)articles of earth which they need for the mechanical process of 
digestion. After the water has been turbid for a short while, trout have invariably 
been observed to take to their food with particular readiness, and probably not merely 
because they had to fast while the water was turbid. 

It is difficult to state the minimum quantity of water for a raising-pond; the tem- 
perature, the saturation of the water with oxygen by a strong fall, and other circum- 
stances will render changes in tlie quantity of water necessary; but no fish-cultural 
establishment should be started without a steady total influx of 0.5 cubic meter (17.7 
cubic feet) of water [»er minute. 

If the ponds can get shade during the hot afternoon hours from rising ground in 
the neighborhood they will be all the cooler, but the condition which will exercise the 
greatest influence on the quantity of fry to be put in the ponds, and on their safety, 

I Intensive Teichwirthschaft. Vou S. 3aSt'6 in Sandfort. From AUgemeino Fiaclicrei-Zeituug, 
No. 24. 1894. H. Jacobson, traaslator. 

311 



312 BULLETIN OF THE UNITED STATES FISH COMMISSION. 

is the depth, which should be as considerable as the nature of the ground and the 
absolute necessity of occasionally draining the ponds will allow. Even if thei'e is a 
heavy flow of water into the raising-ponds, they should not have a depth of less than 
1 meter (3.28 feet); and if it were not desirable to be able at all times to survey the 
bottom of the pond, through the water, throughout its entire extent, I would rather 
have the depth 3 than 2 meters (10 rather that 6A feet). 

The bottom of the imnd should slope gently toward the aperture for letting the 
water off. The enormous pressure of the water, which is necessary in a pond of this 
depth, makes it desirable n(jt to dam up the entire quantity of water, but to obtain 
at least half the depth by digging. It will be found advantageous to construct, if 
possible, several ponds (say four) at one and the same time, having a depth of 1.55 
meters (4.92 feet) and a surface area of about 9 by 20 meters (29.5 by G5.G feet). 

It is necessary that every pond be arranged so that it can be absolutely drained; 
and it is an advantage if every ]iond has its inlet of fresh water independent of 
others. But with two pairs of jxjuds the lower ones should also receive the water of 
the upper ponds. The slopes on the banks and the bottom of the ponds should be 
well planed, and all hiding-places, sticks, stones, etc., should be removed, to provide 
for dragging nets through the ponds, which at a later period becomes necessary. 

It is advisable to sow watercresses (the seed can be obtained from any seedsman) 
on the bottom and slopes of the pond immediately after it has been finished, and let 
in the water only about a week later, unless it is preferred to leave the second pair of 
ponds dry, to serve as reserve for emergencies. Wherever, in intensive feeding, it 
becomes necessary to deprive especially the shy brook trout of every hiding-place, 
the watei'cresses, which will soon grow luxuriantly, will later furnish shade for the 
fish and homes for the small aquatic animals which are as much needed for food in 
these ponds as in natural ponds. Long bean-poles (say, four to every pond) are laid 
in the surface of the water at regular intervals and bunches of watercresses are 
thrown among them; the cresses freely take root in the water and can easily be 
removed before the pond is dragged. 

So far, I have only had reference to ponds dug out of the ground and have ignored 
the existence of raising-ponds constructed of boards or laid in with cement, such as are 
found in many places. These ponds, whose construction is very expensive, can be 
managed very easily, and the i)erpendicu]ar sides afford good shade and a clear view 
of the entire pond. The growth of the fish, however, is very unsatisfactory in them, 
compared with ponds dug out of the ground (not to mention the smaller expense of the 
latter), and the excrements are not put to as good a use as in the earth-ponds, where 
the aquatic animalcula, which serve the purpose of removing refuse excrements, etc., 
thrive much better. I also think that trout make use of earth in digesting food. 

Other fish than trout should of course not be kept in the ponds, and if possible only 
one kind of trout should be kept in each pond (char in the coolest ponds, brook trout 
in the warmer, and rainbow trout in the warmest). It is urgently recommended to 
introduce into the raising-ponds, at the very outset, swamp snails, small crustaceans, 
etc., to furnish the fish as much good natural food as possible and provide a means of 
clearing the ponds of the refuse of food and the excrements of the fish. Wherever 
fish are crowded together' in a small space, and dead food is introduced, the natural 
equilibrium is disturbed, and this should be restored as far as possible by the intro- 
duction of live animalcula. At Sandfort there are, above and between the raising- 
ponds, special smaller basins dug out of the ground, which are thickly covered with 



NOTES ON FtSH-CULTURE IN GERMANY. 313 

vegetation aud whicli successfully answer the purpose of supplying- the water with 
oxygen and live animalcula. For raising these aniiiialcula 1 would not recommend 
ditches with standing water and liquid manure. It is true that these ditches develop 
a vast quantity of suitable live food, but they also produce water-beetles and other 
injurious animals. 

The difficult question as to the proper quantity of fry to be placed in a pond can be 
satisfactorily answered to suit each individual case only. At Sandfort 4,000 young 
fish are placed in autumn in a raising-pond with an area of 180 square meters (1,937.5 
square feet) and a depth of 1.5 meters (4.9 feet), and as the principal object is to 
produce as fast as possible a fish weighing not more than one-fourth pound (the 
favorite weight), all small and weakly as well as all fry of excessive size are eliminated, 
and the normal fish measuring 8 to 11 ceiitimeters (3.1 to 4.3 inches) are used for 
raising. Where artificial food is used, artificially raised and fed fry are the best, as 
fry from natural ponds are as a general rule not so even in size and are not evenly fed. 
I am also of the opinion that they are more inclined to cannibalism than domesticated 
fish. 

The great advantage which a fish-cultural establishment possesses over the 
culture of natural ponds, is in its ability to place its products on the market or retain 
them, just as it suits the proprietor. The natural pond puts its products on the 
market at the wrong time, either in autumn when the season for selling trout has not 
yet commenced in the great fish market, or in spring after Lent is over. No wonder 
that under these circumstances fish-dealers guard their interests by making only 
cheap offers. But fish-dealers also know where they can get fish at a season when 
ice covers the natural ponds, without running any risk from short weight, losses from 
death, and other causes. With some little care, a fish-cultural establishment can 
manage to have its fish ready for sale at the jiroper time and when they will fetch the 
highest price. 

Even if the young fish in course of raising are most carefully sorted, some will be 
retarded in their growth, while others will grow more rapidly than the rest. Those 
whose growth has been retarded (i>robably 10 to 15 jier cent) should be i)laced in a 
reserve pond and fed there; customers for them will be found in the spring. Most 
fish, however, will have their full weight from October to December, and the regular 
rotation of a raising-pond can be completed within one year. Those fish which have 
grown more rapidly than the rest will, in a well-regulated fish-cultural establishment, 
serve for selecting breeders for future campaigns ; and if there are larger ponds it will 
pay (as far as rainbow trout are concerned) to keep these fish for two years longer. 

In stock raising-ponds it is, above everything else, necessary to have normally 
developed and evenly sorted fish; and these are best obtained in autumn from the 
yearling jjonds, immediately after the close of the fisheries. The fish are then in 
prime condition, and, owing to the cooler weather, transportation is cheaper than in 
spring. In the raising-ponds the fish will eat and grow all winter through, and a 
10-centimeter (3.9 inches) fish obtained in autumn will naturally turn out better than 
such a fish obtained in spring. 

As a general rule, it is very difficult to accustom the German brook trout to 
artificial food. It is a shy fish, and must be deprived of every hiding-place, and 
placed in i>retty close confinement to induce it to eat artificial food. But its Scotch 
cousin, the " Loch Leveu," through domestication continued for several generations, 



314 BULLETIN OF THE UNITED STATES FISH COMMISSION. 

has not only lost much of its shyness, but by adapting itself to our circumstances 
has become a Ush very closely resembling the German brook trout, and is ijarticularly 
well adapted to artificial culture. 

Our fish-culture, however, would hardly have reached its i^res'ent height, if we 
had not adopted the two Americans, the char or American brook tront {Salmo 
fontinalis) and the rainbow trout {Salmo irMeun). They must be considered as of 
primary importance in fish-cultural establishments. They will never crowd out our 
brook trout but will maintain a place in the public favor. The char, wherever it is 
known, already fetches a higher price than the brook trout; and the rainbow trout, 
which, owing to its enormously rapid growth, easily becomes too fat, finds a ready 
sale as a three-year-old fish, weighing from 1 to 3 pounds. 

At Sandfort and several neighboring establishments a ready market has rapidly 
been created for all the above mentioned kinds of trout. When sold at the ponds 
they fetch the following prices: Brook trout, rainbow trout, and char weighing one- 
fourth to one-third pound, 3 to ih marks per jiound (71 cents to $1.07); large rainbow 
trout, 2i marks (59 cents). The last mentioned price pays better, as regards large 
flsh weighing 3 to 5 pounds, which require but one young fish for raising, than 3 
marks (71 cents) for flsh weighing one-fourth pound, where four are required to make 
1 pound. It is, of course, not possible to procure in every locality sufficient space for 
raising trout as large as that; in comparatively small ponds the fish will not reach 
such a weight in three or four years, even if there is an abundant supply of fresh 
water and very ample food. 

Fish need, as they grow older, more space and greater depth of water. At 
Sandfort, therefore, the two-year-old rainbow trout which have outgrown the desired 
weight and weigh about half a pound are (to the number of GOO or 700) placed in a 
pond having an area of about 1"^ acres and a dei)th of water of G feet, and there reach 
during one more year the weight of 3 to 4 pounds per fish. It is inobable that the 
same result could be obtained in a smaller pond with a greater depth of water; at any 
rate, 1,400 fish averaging 4 pounds are, from one year to the other, kept in Scotland 
in a pond having an area of 30 by 70 meters (98.4 by 229.G feet) and a depth of 4 
meters (13.1 feet). 

It will be useful to get a proper idea as to the quantity of food required per year 
in a trout-raising establishment of avei'age size and to learn the cost of intensive 
artificial culture as compared with extensive natural culture. It should be i-emembered 
that trout are very settled in their way of feeding and that it is difficult to accustom 
them to a change in the color and consistency of the food. It will therefore be useful, 
from the very start, to select such food as can be obtained regularly and when mixed 
can be steadily given to the fish. It is true that it does not hurt the trout to fast for 
a few days, but regular feeding is nevertheless one of the conditions of success. 

Trout-raising establishments should, with the view to facilitate the sale of the 
fish, not be removed too f;xr from the great highways, and if this condition is fulfilled 
it will also be easier to obtain food. 

Salt-water fish make excellent food for trout and can be obtained regularly and 
cheaply; and these, with the refuse from the slaughter-house, unist l)e i)rincii)ally 
relied on. 

The fish-auctioneers at Hamburg, Altona and Geestemiiude will gladly indicate 
the sources from which salt-watei- fish can be obtained. It is best to take such as are 
sold with the blood and entrails, as the sea scorpion and cod; herring are generally too 



NOTES ON FISH-CULTURE IN GERMANY. 315 

fat. Of slaughter-house refuse, the liver and lungs are the most important, and both 
are excellent. It is urgently recommended that only such food should be bought as 
has passed the inspection of slaughter-house inspectors. Large pieces of animals 
which are not suitable for human food are also dangerous for fish, and only when they 
have been boiled (as is done in some slaughter-houses) so as to bind the albumen 
contained therein, is it advisable to use them. 

Both salt-water fish and the refuse from the slaughter-houses are ground fine 
in a machine made for the purpose (for establishments of the average size 1 would 
recommend No. 91, by Scheffel & Schiel, Miihlheim on-the-Ehine, whi(,-h, worked by 
hand, grinds 100 pounds in an hour) and then mixed; an addition of shrimp flour or 
meat flour is useful and gives consistency to the food. 

According to my exijerience, 5 to C> pounds of such food will be required for 1 
pound of fish, provided the water is kept at the proper temperatiu'e— char, 12° Reau- 
mur (59° F.); brook trout, 14 to 10° Eeaumur (63.5^ to (iSo F.); rainbow trout, 16° to 
18° Eeaumur ((38° to 72.5° F.) — which temperatures can easily be maintained if the 
direction in which ihe sun strikes the ponds and the flow of water through tlie ponds 
are carefully calculated. The cost of raising 1 pound of fish, including cost of admin- 
istration and culture will in an average-size establishment be, at the very highest, 
90 pfennig (21 cents) per pound. For fish weighing from 1 to 5 pounds the cost of 
rearing will be still less. 

It is also recommended to use snails, caterpillars, etc., for fish-food. They will 
form an excellent addition to the above-mentioned articles of food. Even if the expense 
of collecting is rather high, I would give my fish nearly all the food of this kind 
which could be obtained. 

The trout is a very voracious fish. An avei'age establishment which has, e. g., two 
ponds of 4,000 young fish and intends to produce with these 8,000 fish, with a total 
weight of 2,000 pounds, will during one campaign have to procure 10,000 to 12,000 
pounds of food, or on an average 240 to 250 pounds of food per week (say 200 pounds 
of fish and 50 xwnuds of slaughter-house refuse). Even in summer fish-food can be 
kept suiticieutly fresh for three days if placed in large earthen crocks, covered with a 
little salt, and washed by running water. Even average establishments will therefore 
be able to procure twice a week a 100-pound basket of salt-water fish by railroad. 

It is quite evident that, food being so cheap, a profitable intensive culture is 
possible. The greatest danger to be feared is the possibility of epidemics ; this danger 
can not be entirely eliminated, but I am justified in saying that (1) healthy food, (2) 
a suflftcient supply of aijuatic animalcula for destroying the refuse in the ponds, (3) 
ponds dug out from the ground which, after every campaign, are cleaned (both bottom 
and slopes), well supplied with watercresses, and laid dry periodically, will form efficient 
preventives of epidemics. 

In summer the fish should be fed about sunset, otherwise shortly after noon, and 
they should never get more food than about 5 per cent of their average weight. They 
ought not to be fed in sultry weather nor when the temperature is considerably above 
22° Reaumur (81.50 F.). 

I strongly object to feeding-tables in these ponds. The food ought to be thrown 
to the fish with a ladle, and so little at a time that they catch it before it sinks to the 
bottom of the pond. In using feeding-tables there is danger that the attendant, from 
sheer laziness, will pour the entire quantity on the table at once, thereby causing the 



316 BULLETIN OF THE UNITED STATES PISH COMMISSION. 

loss of a good deal of the food by its becomiug watered, etc., not to mention that a 
feeding-table becomes a receptacle for decaying matter and enemies of the fish which 
fear the light of day. 

The duty of tending the iisli should be in the hands of one person ; and, if possible, 
the lish should not be disturbed by visitors. 

Fisli raised for the niai'ket should, as long as the pond is well stocked, be caught 
with a smooth drag net, and the water should be allowed to flow off thoroughly; if 
this is observed their flavor is just as tine as that of the wild fisli, although their flesh 
has not the same degree of firmness. The older fish are not in any way inferior to the 
wild flsh; and the rainbow trout in particular, when older, gains an excellent, salmon- 
like, pure flavor. On some estates, and especially in many factories (particularly 
paper mills) an establishment, as recommended above, will be possible and profitable 
and might, on account of the better supervision, be founded dose to the house, in a 
simpler manner and within a small space. I have laid special stress on the advantage 
of such an intensive culture conducted on a small scale, but it is certain that it will 
also afford a good deal of pleasure to the cultivator. 

If, as in many cases, there are, near factories, dams with spring water which can 
be let oif and which are to be devoted to intensive culture, though the area exceeds that 
referred to above, it will be advisable to put in a smaller number of fish, as in such 
cases the brook trout will not very readily take the food provided for it. I would 
confine the culture to the American fish, imrticularly the rainbow trout, and from the 
start arrange for a two year's rotation and for raisiiig large fish. The largest possible 
fiy should be selected (even if the price should be somewhat high), and not more than 
2,000 young fish should be set out per acre. The American fish will in such ponds 
take to the food at once ; and as far as the rainbow trout are concerned, it does not 
matter if there is a temporary stagnation in the i)ond. 

In conclusion, I would state, as the leading principles of intensive pond-culture, 
the following: 

(1) Plenty of cool water and deep ponds. 

(2) Use evenly sorted young fish which are accustomed to the food which is to be 
provided for them. 

(3) Stock the pond pretty thickly, especially with the fry of the char and the 
rainbow trout. 

(4) Never use inferior food. 

(5) At proper times clear the ponds of all fish, dry the ponds thoroughly, and clean 
tliem well. 



NOTES ON FISH-CULTURE IN GERMANY. 317 



NOTES BY S. JAFFE ON THE REARING OF YEARLING TROUT AT SANDFORT.' 

Keijeated inquiries as to the manner in which yearling trout are raised at Sandfort 
have induced me to give a brief sketch of our local experiences and manipulations. 
The results regularly obtained here (and which can be obtained in other phxces by 
similar methods, perhaps slightly modified to suit local conditions) presupposes a large 
and regular business, with the fundamental conditions of a regular supply of suitable 
water and ample opportunities for obtaining fresh food. The establishment must, 
moreover, have one suitable person devote himself entirely to the propagation of the 
young fish. It is also important, according to the Sandfort method, to know from 
what trout eggs the young fry are hatched. Fry whose x>rogenitors were accustomed 
to artificial food are more easily and safely raised and (I here refer to the ditierent 
varieties of the/«/'/o) the result will be all the better the further back the pedigree 
of the tame generation goes. These experiences agree with those of English and 
American establishments, like the other experience, that the fish if possible shall leave 
the egg in the water in which it is to live during its helpless period, which extends 
into the summer. 

The manipulations employed in raising /or/o and the American varieties of the 
trout are nearly the same in the Sandfort establishment. Eggs of both kinds are 
hatched in thin layers in wooden troughs about 4 meters (13.1 feet) long, which, on 
the inside, are charred to the depth of 1 centimeter (0.39 inch). The breadth in the 
clear is 22 centimeters (S.65 inches); height, the same; the depth of water is G to 8 
centimeters (2.4 to 3.15 inches). The young fry, immediately after they have left the 
eggs, are placed in freshly cleaned hatching-troughs (about 15,000 in a box), which at 
the end have obli(|ue sieves of perforated sheet-zinc (perforation No. 0). The fry are 
not counted (the eggs are counted immediately before hatching), as the least touch will 
affect the mucous skin of the young lish and lay the foundation for fungous develop- 
ment. Healthy young fish will, wherever unfiltered brook water is used, entirely 
clean the bottom of the box, and until the loss of the umbilical bag little remains to 
be done except an occasional cleaning of the sieves. Dnring this period the young 
fish lie densely packed close to the inlet on a space extending hardly 0.25 meter (10 
inches) in length; and toward the end of the umbilical period the current of water 
passing through the box — which hitherto has been about 20 liters (5.3 gallons) per 
minute and per box — is strengthened and the solid lids of the box are replaced by lids 
made of fine wirework. From the very beginning of the feeding period a strong light 
is good for the young fish. 

As soon as the young fish begin to look around for food it should be given them. 
The food consists of fresh hog-liver (that over a day old is dangerous), which is put 
through a small meatchopper and then, with a knife, forced through a finely per- 
forated piece of sheet zinc (perforation No. 4, pin size) and afterwards mixed with a 
raw egg, in the proportion of two eggs to one hog's liver. During the first time, one 
hog's liver and the attention of one person are sufficient for daily serving four boxes, 
each containing about 15,000 young fish. 

' Die Aufzucht vou Jalirlingen iu Sandfort. Vou S. JaffcS. From AllgemeiQe Fischerei-Zeitung, 
No. 9, 1895. H. Jacobson, translator. 



318 BULLETIN OF THE UNITED STATES FISH COMMISSION. 

This food is given by tlie teaspoouful from a feeding spoon, wliicli is covered with 
zinc (perforation No. 4 for char, No. 6 for other salmonoids) and from which the pulp 
gradually sinks under the water. The young fish take to this food very readily, but 
oidy when it is driven toward them by a strong current. Trout will not, till far into 
the summer, skirmish for food. The font in al is and fario act very differently in taking 
their food. The fario kinds (and I include among these the Scotch Loch Leven) 
remain close to the bottom, and only a inoveinent of the head indicates that they are 
taking food; the fontiiiaUs are distributed throughout the entire depth of the water 
and almost rush at the food. In order to satisfactorily raise the young lish it requires 
extraordinary patience and great care not to let any food fall to the l)ottom unused. 
The young fish soon learn to gather at the head of the trough, ami the sooner they 
do this the better are the prospects of success. 

Fry which have been badly raised or hatched — and I include among these both 
fry from too young parent fish, apparently looking very nice in the eggs, and those 
which in a closely packed hatching-apparatus have not received a suificient supply of 
oxygen in the egg during hatching — will perish at this stage ; and I can not snfliciently 
urge the necessity of obtaining eggs (unless they have been laid and hatched in the 
establishment itself, which is of course preferable) only from thoroughly reliable 
establishments, whose eggs may be somewhat higher priced but whoso careful 
management is a sufficient guaranty for a good article. 

Failure to raise young fish is in many cases caused by mistakes made in remote 
stages of the development of the eggs or the i^arent fish. Whenever fry jjerish it 
is by DO means right to seek the cause in recent occurrences, as the feeding of the 
liarent fish and the hatching of the eggs may have had a great deal to do with it. 
The great care which is essential for i)rodacing high-grade eggs will naturally limit 
their production and will justify the higher price asked. 

Healthy fry will, as soon as they commence to eat, give very little trouble. In 
addition to the utmost care in giving the food to the young fish it will be necessary 
to tlioroughly clean the boxes at least once a week. A nail-brush with strong bristles 
will answer this purpose admirably, and, after the water has been let out of the 
hatching-trough until it is only an inch deep, the sides are thoroughly brushed, 
commencing at the head. The young fish skillfully evade the brush and are rarely 
injured. From the commencement of the feeding period the water in each trough is 
twice a day made thoroughly turbid by jjouring in a bucketful of water and rich sod 
soil mixed. After this has been done tlie young fish will always take their food more 
readily. After tliey have been thoroughly accustomed to take the food the troughs 
are emptied by taking out the bung at the end and the young fish are swept into 
large buckets with the water. Prior to this the Saudfort " nurseries" (large raising- 
boxes) are laid at anchor in the open bed of the brook near the hatching-house by 
being fastened to boxes and poles. 

These "nurseries" are strong boxes made of wood IJ inches thick with a well- 
finished and tightly fitting bottom of wood three-fourths inch thick. The sides are 
covered with plates of perforated zinc (perforation No. 9) and the boxes are furnished 
with closely fitting lids, which are covered with wirework and admit as much light 
as possible. The boxes should be placed in a strong current, and the stronger the 
pressure of water which the young fish have to resist the stronger and healthier they 
appear to be. The Sandfort brook is a mill stream with a very irregular current. 



NOTES ON FISH-CULTURE IN GERMANY. 319 

frequently rendered turbid by rainstorms, and with a deptli of water varying from 
0..J to ] meter (l.(i to 3.-*.s feet). x\.fter tbe water bas become turbid the yimng- fish 
appear to be in particularly line condition. Each box now contains 10,000 to 20,000 
young tisb — tbe smaller number if brook trout, tbe larger if rainbow trout. It is 
customary in Sandfort to pour tbe tiny fisb, immediately after they have been hatched, 
into these "luirseries" and to begin the feeding process, which with the rainbow trout 
is very easy, in these boxes. As the young fish grow the food is gradually changed 
to calf-liver without egg and then to beef-liver, which in June is fed to the flsh just 
as it comes from the chopper. The feeding process has now become exceedingly easy 
and consists in simi)ly throwing the food into the boxes with a common spoon. One 
person can easily serve six and later even ten boxes. 

In June the young fish are transfen-ed to earth-ponds and sorted closely according 
to their size. Henceforth the losses will be very few. The use of "nurseries," 
especially for young rainbow trout, has the advantage of great safety and cleanliness. 
The boxes are, after every campaign, covered with a coating of asphalt lac, and 
thus last for years. While the young fry are in the boxes, the earth-ponds can be 
thoroughly cleaned and dried; and as they are tilled again late in the season (in 
June) III limit is thus set to the development of larva and vermin. The cost of such a 
box, according to its more or less careful finish, varies from 50 to 70 marks (*11.00 to 
$10.(j(i), which can hardly be considered too much, in view of the comparatively high 
value of the yearlings produced. 

Of fourteen boxes which in 1803 were used in the Sandfort establishment, those 
containing rainbow trout yielded the best results. One box, which had been stocked 
with young fry from 20,000 eggs, produced in June over 17,000 young fish. It is 
possible to keep the young fish in the boxes till jSTovember, in smaller numbers (up to 
5,000); but, ttom June on, the growth in the earth ponds is much more satisfactory 
than in the boxes, especially as in ponds filled late in the season young fish find an 
ample supply of natural food, such as Cyclops and other small crustaceans, and later 
the small pond-snails. 

The only objection which could be raised against this system, which is appai-ently 
based entirely on artificial food, is that such fish would not be able to get their food 
in a brook or open pond. But apart from the fact that the instinct for seeking food 
and for self-preservation is exceedingly strong in all animals, the well-fed young fish 
from the fish-cultural establishment will surely carry with him a greater "reserve of 
food than the hungry wild flsh, and would be more apt to push the latter away from 
the food than i)erish. Fish can (and this is hardly sufficiently known) live a long time 
without any food Avhatever, and even lose 50 per cent of their weight without perish- 
ing or losing the faculty of seeking food. To see how fish which have just been fed 
will go gnat-hunting, it will be sufficient to watch yearling ponds, like those at Sand- 
fort, some afternoon or evening. The eye can not quickly enough count the flsh which 
leap out of water for gnats. If this is not sufficient proof all that will be necessary 
will be occasionally to dissect an artiflcially raised fish, and see what its little stomach 
contains, in addition to the artificial food, in the shape of snails, gnats, and small 
crustaceans. 



320 BULLETIN OF THE UNITED STATES FISH OOMMISSION. 



PISH-CULTURAL METHODS AT THE AGRICULTURAL SCHOOL AT FREISING.' 

Xofc far from Munich is the little town of Freisiiig, one of the most ancient places 
in Bavaria. At this i)lace the ancient Benedictine convent of Weihenstephan has 
been converted into a school of agriculture and a modem brewery. When I learned 
that instruction in flsh-culture was given at this school I was glad to accept an 
•invitation of Professor Steuert, who has charge of the instruction in fish-culture 
and the care of fish, to visit Weihenstephan, and on December 12 I went there to 
study the metliods pursued. All the arrangements are exceedingly simple. As the 
buildings of the ancient convent lie very high above the stream wuich Hows through 
the town, the supply of water for the entire institution has to be forced up by a 
steam pump. From the general reservoir a small pipe leads the water to the phice 
where the fish-cultural section of the establishment is located. 

This section, which is intended both for hatching and reai-ing trout, consists of a 
large box whose bottom is elevated a little above the ground. On this stand two Le 
Petit apparatus, which serve as filters, the hatching a^jparatus, and, when the fish 
have developed, an apparatus for raising larvfe. Fig. A shows the appearance of the 
box. The water flows into the apparatus through the pipe r, is filtered, flows through 
the box and out into a collector at the side of the apparatus. Thence it is led into the 
collecting pipe E, which pours the water over a wheel wt, which is in the ti'ough <, 
above the surface of the water, and is thereby kept in rotation. In the trough t the 
young fisli are generally kept till they are seven to eight months old. At the time of 
my visit Professor Steuert had in tbis trough both rainbow trout, which had been 
hatched last spring, and brook trout which had been used lu autumn for supplying 
roe. All of these fish had been fed during the last few months on cheese, which 
seemed to have made them grow healthy and strong. 

Fig. B gives a profile view of the apparatus. To keep out the cold of winter, the 
inner walls of the box had been lined with straw /;. We found the water warm enough 
to prevent all danger of freezing during ordinary winters. As both the Le Petit 
apparatus and the wheel m (fig. A) — tlie so-called "feeding wheel" — have been 
thoroughly tested and found to answer, a drawing and a short explanation of the 
apparatus may not be out of place. 

Fig. 1 shows the apparatus, viewed from the side, aiul a section of part of it. At 
a the water enters the apparatus, which is filled for about two-thirds of its height 
with gravel c, serving as a filter. Above this layer of gravel there is a perforated 
vessel (sieve), on the bottom of which the fish eggs are spread. Through the pipe d 
the water flows out into the collector above referred to. The apparatus is closed by 
a lid which has a small glass window at the top. After the young fish have been 
batched and jjlaced iu the trough, and have grown so large that they begin to snap 
after larger morsels of food, the apparatus is made to answer another purpose (fig. 3.) 
The gravel is emptied out, the perforated \essel is taken away, aiul a frame with a 
coarser grating c is laid in the apparatus. On this frame meat (refuse from butcher 
shops) is placed, the lid is jjut on, and a cover is placed over the little window. 
Through the opening b flies go to seek the meat and lay their eggs thereon. 



I Letter from Bavaria, translated by H. Jacobson, from Fiskeritidskrift for Finland, No. 2, 
Heluingfors, February 17, 1895. 



Bull. U S. F, C 1895 Notes on Fish-CuHute .n Germany. (To lace page 320.) 



Plate 55. 




R^B. 




Fig. 3 



Fig. 4 



HATCHING APPARATUS AT FREISING. 



NOTES ON FISH-CULTURE IN GEEMANY. 321 

When the hirvie have developed in the meat, the window is opened, so as to cause 
the larvie, through the influence of the light, to go to the bottom. A stream of water 
is now let in through a, which drives the larva', into the jiipe o (fig. 2). Below this 
the trout gather in schools and watch for the food carried out with the water, with 
such eagerness that it is impossible for the larvae to escape their voracity. On this 
fare the young trout thrive marvelously, and grow large and strong. The greatest 
advantage, however, of this arrangement is in the circumstance that there is no 
refuse to render the water impure or actually dangerous for the young fish; which is 
greatly to be feared when young fish are fed on liver or similar articles of food. 

The so-called "feeding- wheel" consists of a cylindrical tin tray abont 14 centi- 
meters (5J inches) iu diameter, and 5 centimeters (nearly 2 inches) deef) (fig. 3). The 
outer riui of the cylinder is perforated at d d d { fig. 4), and is provided with paddles 
e e e e e. The cylinder is moreover provided with an axletree. As this rests on two 
supports, and as a stream of water is forced against the paddles in the direction 
of the arrow (fig. 3), the cylinder is made to rotate, which motion causes the finely 
ground food inclosed therein to be gradually ejected through the apertures (Z (7 d. 
The young fish, which soon find this ont, gather under the wheel— the waterfall — and 
catch the food. This arrangement has all the greater practical importance iu feeding 
young trout, because, when the fish are fed by hand, they never get that portion of 
the food which falls tu the bottom. 



THE COURSE OF INSTRUCTION OF THE BAVARIAN FISHERY ASSOCIATION.' 

I had the pleasure of receiving an invitation from Professor Steuert, who is a 
member of the Bavarian Fishery Association, to attend its course of instruction, 
where both theoretical and practical instruction in fish-culture are given. The 
meeting was held in the old building of the Eoyal Academy of Fine Arts, in Munich. 
The excellent work of the association was spoken of, and attention was called to the 
fact that the results were not solely due to j)ractical work, but also to the aid which 
the association had at all times received from the scientists of the Munich University. 
Waters which were formerly Ashless had been stocked with suitable kinds with such 
success as to give them a perfect wealth of fish, 

A lecture by the well-known zoologist, Dr. Hofer, lasted from 10 a. m. to 7 p. m., 
with a recess of two hours. The lecture was iu three j)arts: (1) Biological descrip- 
tion of the kinds of fish which form the subject of the association's fish-cultural efforts; 
(2) the proper care and protection of the fishing waters; (3) fish-food. 

Among the fish which the association had cultivated the speaker mentioned: 
Carp, tench, perch, bass (American), eel, trout (rainbow trout), German brook trout, 
American brook trout, and Alsace trout (a cross between the American brook trout 
and the European trout), grayling, gwiniad, etc., and finally the pike. 

The speaker said that the carp was not indigenous to Germany, but was now 
found everywhere. Ue exhibited a number of select carp, which by cultivation had 
reached large and well-rounded dimensions, and which differed very much from the 
so-called peasant's carp, a small and insignificant-looking fish. There are two kinds 



'Letter from Bavaria (concluded), translated by H. Jacobson, from Fiskoritidskrift for Finland, 
February 17 and March 16, 1895, Helsingfors, Finland. 

F. C. B. 1895—21 



322 BULLETIN OF THE UNITED STATES FISH COMMISSION. 

of select carp in Germany, viz, Bohemian, which has a more elongated, and the 
Galiciaii, which has a roiiuder shape. 

It was formerly thought that carp lived ou vegetable food, but it is now definitely 
settled that snails, crustaceans, and other small aquatic animals form its principal 
food. The carp gets albumen and soluble hydrates of carbon also from plants, and in 
many places it is therefore fed on boiled potatoes. For spawning the carp need water 
having a temperature of at least 14° to 15° Reaumur (03.5° to 65.75° F.) ; 18° Eeaumur 
(72.5'3 F.) may be considered the best average temperature for the carp, and it can 
even stand 25° to 28° Eeaumur (88.25° to 95° F.) without difficulty. With abundant 
food it can reach tlie weight of 4 pounds at the age of one year. Under ordinary 
circun^stances it weighs 1 pound at two years, 2i to 3 pounds at three years, and 3 to 
5 i)ounds at four years. In many localities there is a demand for carp of a certain size, 
and owners of carp ponds must bear this in mind. An idea of the vast extent to which 
carp are raised in Germany may be gathered from the circumstance that Prince 
Schwarzeuberg annually spends 250,000 florins ($100,000) for ground meat for feeding 
his carp. Mr. Burchardt, a prominent fish-culturist, received from Prince Hatzfeld 
40,000 marks for bringing the prince's ponds up to a higher state of productiveness. 

Perch are now quite common in Bavaria, but are not well suited for ponds. In 
their place American bass, both small and large mouth, have recently been introduced. 
The large-mouth, which can stand water of a high temperature, reaches the weight of 
20 jionnds. The small-mouth bass, ou the other hand, requires colder wafer. The 
fish increase i-apidly and with certainty, especially as the young are protected from 
enemies by their j)areuts. For spawning they require a rocky bottom or one covered 
with coarse gravel. As i)ercli grow slowly and generally do not reach a greater 
weight than 3 pounds, they should bo supplanted by this more valuable fish. In 
Munich bass bring 2A marks (50.5 cents) per pound. 

The raising of eels is exceedingly profitable in Germany. One huiulred young 
eels set out in a poiul yielded 2,000 kilograms (4,410 pounds) of eels after three years. 

The trout is very generally raised in Germany. It I'equires running water, but 
some kinds thrive in ponds. The common brook trout (Salmo fario) is not found in 
water of more than 18° Eeaumur (72.5° F.). It is a predaceous fish. 

The rainbow trout {Salmo irideus) which comes from the west coast of America, 
can stand both cold and warm water, the latter up to 25° Eeaumur (88.25° F.). This 
alone makes it suitable for fish-culture. It sjjawns in spring, April and May. In 
cold water it reaches the length of 12 centimeters (4.7 inches) during the first year; 
22 centimeters (8.7 inches) during the second year; 28 centimeters (11 inches) during 
the third year, and is then ready to spawn. The male fish are ready one year sooner. 
Under very favorable circumstances, and in water of high temperature, three- year-old 
rainbow trout have reached a weight of 5 pounds. It is much easier to raise this kind 
of trout than the common brook trout. It takes food much easier, is not predaceous, 
and is admirably adapted for pond-culture. 

Of late years a brook trout (SalveUnus fontinalis) imported from America has 
been raised considerably in Germany, It has a dark-red belly and fins. It is found 
in very cold water, having a temperature of 7° to 8° Eeaumur (47.75° to 50° F.), and 
grows faster in such wati r than other kinds of trout. 

The speaker exhibited a cross between the German and the American brook trout, 
which has been called the Ahace trout. It is fatter and larger than the American and 
is best suited for small streams. 



NOTES ON FISH-CULTURE IN GERMANY. 823 

As regards tlio care of fish water, great stress was laid on the proper paius in 
establishing and maintaining the spawniug- places. In Prussia certain spawning-places 
were protected all the year around in all larger sheets of water. The speaker did not 
consider it useful to place entire bays and coasts under protection, as these places 
then become favorite places of sojourn for predaceous fish. Arrangements should be 
made not to place in ponds too many kinds of fish living on the same kind of food, 
but rather such as live on different kinds of food. In this respect special regard 
should be had to shoal-water fish and to deep-water fish. Fish watei's cared for in 
this manner have yielded good results in Bavaria. 

As regards the pike the speaker stated that it was one of the most unsatisfactory 
fish for raising, on account of its voracity. Experiments had shown that it took 47 
pounds of meat to raise 1 pound of pike. A beginning, however, had recently been 
made to raise pike in special ponds having a good supply of small fish. This had, for 
instance, been done iu i)ouds having too large a stock of carp. 

In regard to artificial impregnation^ the speaker stated that, since the so-called 
" dry method " had been adopted, the percentage of impregnated eggs had increased 
from 50 to 80 or 90 per cent. Numerous investigatious had shown that the spermatozoa 
of the male fish do not live iu the water longer than 22 seconds, during whi(^h short 
time the eggs are not nearly all impregnated. Immediately after impregnation the 
eggs are very tender to the touch; and the fact had been positively ascertained that 
if a few days after impregnation the roe is disturbed on the frames in the apparatus, 
many eggs wdl perish. The germ in the egg is specifically lighter than the fluid 
contained in the shell, for which reason the germ always rises to the top. If the egg- 
is turned, the germ again rises to the top, and this causes such a disturbance as to 
make the impreguated egg die. This does not apply, however, to gwiuiad, perch, and 
some other kinds of fish, whose roe develops best if it is well stirred in apparatus 
specially constructed for the purpose. 

The speaker finally showed, greatly magnified, the principal small aquatic ani- 
mals which serve as ft)od for fish. Experience had shown that Daphnia — very small 
crustaceans, most of them measuring no more than 1 to 2 millimeters iu length (0.04 
to 0.08 inch) — if properly t eated, can be brought to a great degree of productiveness. 
The method is very simple. A ditch or small pond is filled with dry leaves, suitalile 
aquatic phuits, and manure (opinions differ as to the kind of manure to be used); a 
number of Daphnia are planted there and under the inflvrence of the summer heat 
develop very rapidly. If the water in the ditch is allowed to flow through a pipe into 
the Y)0ud where the young trout are kept, the fish will thus be supplied with a sufficient 
quantity of natural food. When the fish are larger they are fed on larva- of flies raised 
iu Le Petit's apparatus. As the larviii often grow too large for the fish, this difliculty 
is obviated by placing a fine grating before the opening of the apparatus so that only 
smaller kinds of flies can enter and lay their eggs; whereby, of course, snmller larvai 
are obtained. As the air becomes C(joler toward autumn the young fish are fed on the 
roe of salt-water fish (especially cod roe), which can be bought very cheap. When- 
ever the temperature is higher, the roe should be slightly salted and afterwards well 
soaked before it is fed to the fish by means of the feeding- wheel. 

After the fish have grown they are distributed iu small ponds measuring 15 to -:0 
square meters (101.5 to 215.3 square feet), which are always kept supplied with 
aquatic plants producing fish-food. The trout are now fed on a mixture of 30 per 



324 BULLETIN OF THE UNITED STATES FISH COMMISSION. 

cent blood and 70 per cent flour, dried and pressed through an apparatus which 
makes it come out iu the shape of worms. Grown trout may also be fed on liesh 
refuse from butcher shops, but there should be an ample supply of fresh water in the 
ponds and suitable aquatic plants, in case the trout are fed on such refuse. Two- 
year-old trout are most in demand in the fish-markets. 

The Starnberg Fish-Cultural Establishment, which belongs to the Bavarian 
Fishery Association, is near the little town of Starnberg and the large lake of the 
same name. Tliis establishment, which is not very favorably located, was considerably 
enlarged and improved two years ago. The supply of water is furnished almost direct 
by the seven springs from which the little stream called Der Sieben Quellen Bach — 
the Seven Springs Brook — takes its origin. As the fall is but short and not very 
abruxit the water is led into the hatching-house through an iron pipe and forced to the 
height needed for the apparatus. On the higher bank of the stream a great many 
ponds have been dug, in which tront of different ages and of different kinds are raised. 
Mr. Le Petit has made several experiments in crossing different kinds of trout. He 
finds that it is of the greatest importance in what order the sex is employed. 

The establishment yields a net revenue of 3,000 marks per annum ($714), and is 
expected to yield a great deal more after everything is put in proper working order. 
I was informed that some private establishments yield an annual revenue of 15,000 
marks ($3,570). 

The visitors witnessed the so-called " striking" of trout, i. e., the impregnation of 
trout eggs. In doing this, Mr. Le Petit, who was considered to possess great skill and 
experience in these matters, employed a method halfway between the so-called dry 
and wet methods. First the roe was squeezed into a tin vessel and then the milt from 
the male fish. Then water was poured in the vessel; the milt of one more male fish 
was squeezed into it; the whole was thereupon stirred witii the hand, the water was 
poured off, and tlie roe was slightly rinsed with the remnant of the water. After the 
eggs, imiiregnated iu this manner, had been allowed to stand about five minutes in 
clean water they were placed in the apparatus for further development. The result of 
the impregnation was stated to have been very favorable, as high as 00 j)er cent.' 

As the water used in the establishment has a natural temperature of 6° Celsius 
(42.8° F.), the eggs develop very rapidly, so that the eye-spots become visible after 
.^6 days. The quantity of water used is 2.3S gaUons a minute for each apparatus. 

In January I again visited the establishment to take further observations of 
some of its arrangements, and during the same trip I also visited the fish cultural 
establishment near Miihlthal belonging to Prince Ludwig of Bavaria. This was 
founded two years ago, and appears to be arranged in a very simple and practical 
manner. Tlie supply of water is furnished by a large spring. Here I had an 
opportunity to see a very large number of rainbow trout, born April, 1894. These 
trout, which were of considerable size for their age, were crowded together in a dense 
mass below a "feeding-wheel" containing cod roe. In an area of about 400 square 
meters (4,305.0 square feet), 10 small ponds had been dug, in which fat trout of 
difl'erent ages were basking in the sunshine. The water is introduced into these 
I)onds through iron pipes. 

' Special stress is laid ou the fact that it cost a good deal to gain the exj)erience that only trout 
seven to eight mouths or, better still, oue year old, guarantee the reproduction of trout in waters 
which are to be stocked with these fish. 



002 861 286 2 « 



